#include <iostream>
#include <cstdio>
#include <cstring>
#include <algorithm>
using namespace std;

int main()
{
    int n, m;
    scanf("%d%d" , &n, &m);
    if (n % 3 == 2)
       n = (n / 3) * 2 + 1;
    else n = (n / 3) * 2;
    m -= m / 5;
    printf("%d", n * m);
    return 0;
}